Significant Accounting Policies Level 4 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016
Contract with Customer, Asset, Net	$ 12
Inventory, Net			$ 210
Restricted Cash and Cash Equivalents, Current	18			$ 18
Net Cash Provided by (Used in) Investing Activities	25	$ (26)
Change in cash and cash equivalents	(2)	(73)
Cash and Cash Equivalents, at Carrying Value	95			97
Restricted Cash	18	16		18	$ 17
Cash and cash equivalents (including restricted cash of $0 and $18, respectively)	113	123		115	196
Other current assets	56		56	44
Accumulated deficit	(2,976)		$ (2,963)	(2,964)
Net sales	946	870
Cost of sales	789	737
Gross Profit	157	133
Finished and in-process goods	255			221
Selling, general and administrative expense	82	79
Operating Income (Loss)	76	53
Other Nonoperating Income (Expense)	1	(2)
Previous Accounting Guidance [Member]
Increase (Decrease) in Restricted Cash	0	1
Net Cash Provided by (Used in) Investing Activities	25	(25)
Change in cash and cash equivalents	(2)	(72)
Cash and Cash Equivalents, at Carrying Value		107			$ 179
Previous Accounting Guidance [Member]
Inventory, Net	265
Other assets, current under previous accounting guidance	44
Accumulated deficit under previous accounting guidance	(2,978)
Net sales	945
Cost of sales	789
Gross Profit	156
Selling, general and administrative expense		77
Operating Income (Loss)		55
Other Nonoperating Income (Expense)		4
Adjustments for New Accounting Pronouncement [Member]
Inventory, Net	(10)			(11)
Increase (Decrease) in Restricted Cash	0	(1)
Other current assets	12			12
Accumulated deficit	2			$ 1
Net sales	1
Cost of sales	0
Gross Profit	$ 1
Selling, general and administrative expense		2
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Operating Results		(2)
Other Nonoperating Income (Expense)		$ (2)